Radar ambiguity resolution method, device, medium, equipment and program product

Abstract

The invention discloses a radar ambiguity resolution method and device based on staggered transmitting frequencies, a medium, equipment and a program product, and belongs to the technical field of radars. The method comprises the following steps: transmitting at least two mutually interlaced linear frequency modulation transmitting waves by using a radar; calculating intra-frame distance fast Fourier transform of the current frame signal of the linear frequency modulation transmitting wave to obtain beat frequency of the linear frequency modulation transmitting wave, and calculating Doppler fast Fourier transform of the current frame signal of the linear frequency modulation transmitting wave to obtain Doppler frequency of the linear frequency modulation transmitting wave; and judging a size relationship between a center frequency shift value between the odd linear frequency modulation transmitting wave and the even linear frequency modulation transmitting wave and a preset threshold value, and calculating to obtain an intra-frame fuzzy multiple of the linear frequency modulation transmitting wave by using the beat frequency and the Doppler frequency of the linear frequency modulation transmitting wave. According to the invention, the radar waveform is designed, so that the distance and the radial speed can be accurately measured with relatively high precision and resolution under the condition of multiple targets in a complex scene.

Description

Technical Field

[0001] The present application relates to the technical field of radar, and particularly to a radar ambiguity resolution method, device, storage medium, electronic device, and computer program product based on staggered transmit frequencies. Background Art

[0002] With the development of society, new technologies and new devices are emerging continuously. The development of millimeter-wave radar has faced more and more challenges. The simple target detection and positioning functions of traditional radars can no longer meet the application requirements. In the actual application process, it is necessary to know as much detailed information about the target as possible, such as information about the target's distance, speed, angle, and characteristics. Therefore, multi-functionality and intelligence have become the development trend of automotive radars.

[0003] For radars applied to automobiles, radars with transmit signals such as continuous wave (CW), frequency shift keying (FSK), and chirp have been proposed. The performances and computational complexities of radars using the above transmit signals are completely different. However, the radar using FSK cannot distinguish multi-target information within the beam range. Although the radar using CW has the characteristics of simple structure, low cost, and high integration, it cannot effectively detect the target distance. The radar with chirp waveform has the ability to extract the distance and speed parameters of multiple targets and has become a commonly used waveform for automotive radars.

[0004] Although the existing chirp waveform has the ability to extract the distance and speed parameters of multiple targets, it calculates the target's distance and speed parameters by pairing targets between frames and then using the Chinese Remainder Theorem to calculate the velocity ambiguity number. However, using this method, due to the random changes in the electromagnetic space and scene, there are certain errors in the target distance and speed between frames. Therefore, when pairing targets, the velocity error under the correct ambiguity multiple may be greater than the velocity error under the incorrect ambiguity multiple. Especially as the frame duration increases, multi-targets with similar distances are prone to incorrect pairing, which may lead to incorrect target velocity estimation. Summary of the Invention

[0005] Aiming at the problem of incorrect target velocity estimation existing in the prior art, the present application mainly provides a radar ambiguity resolution method, device, storage medium, electronic device, and computer program product based on staggered transmit frequencies.

[0006] To achieve the above object, the first technical solution adopted by this application is: a radar ambiguity resolution method based on staggered transmit frequencies, which includes: using a radar to transmit at least two interleaved linear frequency modulation (LFM) transmit waves and receiving the LFM transmit waves returned by the target. Among them, there is a center frequency shift between two adjacent LFM transmit waves, and at least two interleaved LFM transmit waves include odd LFM transmit waves and even LFM transmit waves; calculating the range-direction fast Fourier transform (FFT) of the current frame signal of the LFM transmit wave to obtain the beat frequency of the LFM transmit wave, and calculating the Doppler-direction FFT of the current frame signal of the LFM transmit wave to obtain the Doppler frequency of the LFM transmit wave; judging the magnitude relationship between the center frequency shift value between the odd LFM transmit wave and the even LFM transmit wave and a predetermined threshold, and calculating the in-frame ambiguity multiple of the LFM transmit wave by using the beat frequency and Doppler frequency of the LFM transmit wave. Among them, when the center frequency shift value is less than the predetermined threshold, performing in-frame non-coherent integration, constant false alarm rate (CFAR) detection, and in-frame velocity ambiguity resolution processing on at least two adjacent LFM transmit waves in sequence to obtain the in-frame ambiguity multiple of the LFM transmit wave; when the center frequency shift value is not less than the predetermined threshold, performing in-frame non-coherent integration, CFAR detection, in-frame CFAR detection point pairing, and in-frame velocity ambiguity resolution processing on the even LFM transmit waves in at least two adjacent LFM transmit waves in sequence to obtain the in-frame ambiguity multiple of the LFM transmit wave; estimating the velocity of the target according to the in-frame ambiguity multiple to obtain the information of the target.

[0007] Optionally, using a radar to transmit at least two interleaved LFM transmit waves includes: each LFM signal of the LFM transmit wave has the same bandwidth, frequency modulation slope, and pulse width.

[0008] Optionally, when the center frequency shift value is less than the predetermined threshold, the Doppler frequencies of the odd LFM transmit wave and the even LFM transmit wave are the same, the influence of the Doppler frequency on the beat frequencies of the odd LFM transmit wave and the even LFM transmit wave is small, and the range and Doppler positions corresponding to the odd LFM transmit wave and the even LFM transmit wave returned by the target are the same.

[0009] Optionally, when the center frequency shift value is less than the predetermined threshold, performing in-frame non-coherent integration, CFAR detection, and in-frame velocity ambiguity resolution processing on at least two adjacent LFM transmit waves in sequence to obtain the in-frame ambiguity multiple of the LFM transmit wave includes: calculating the ambiguous Doppler frequency of the LFM transmit wave by using the beat frequency and Doppler frequency of the LFM transmit wave; calculating the in-frame ambiguity multiple of the LFM transmit wave by using the ambiguous Doppler frequency, the pulse period of the LFM transmit wave, and the center frequency shift value between the odd LFM transmit wave and the even LFM transmit wave.

[0010] Optionally, when the center frequency shift value is not less than a predetermined threshold, non-coherent accumulation, constant false alarm rate detection, pairing of constant false alarm rate detection points within a frame, and velocity ambiguity resolution processing within a frame are sequentially performed on at least two adjacent chirp emission waves. Obtaining the ambiguity multiple within a frame of the chirp emission wave includes: when the center frequency shift value is not less than a predetermined threshold, using two-dimensional fast Fourier transform to perform non-coherent accumulation of even-numbered chirp emission waves within a frame on at least two adjacent chirp emission waves in sequence.

[0011] Optionally, when the center frequency shift value is not less than a predetermined threshold, there are differences in the Doppler frequencies of the chirp emission waves. The influence of the Doppler frequencies of the chirp emission waves on the beat frequency is small, and the distances and Doppler positions corresponding to the odd-numbered chirp emission wave and the even-numbered chirp emission wave of the target return are the same.

[0012] The second technical solution adopted in this application is: a radar ambiguity resolution device based on staggered emission frequencies, which includes: a signal wave emission and reception module for using a radar to emit at least two interleaved chirp emission waves and receive the chirp emission waves returned by the target. Among them, there is a center frequency shift between two adjacent chirp emission waves, and at least two interleaved chirp emission waves include odd-numbered chirp emission waves and even-numbered chirp emission waves; a parameter calculation module for calculating the beat frequency of the chirp emission wave by performing fast Fourier transform in the range direction of the current frame signal of the chirp emission wave, and calculating the Doppler frequency of the chirp emission wave by performing fast Fourier transform in the Doppler direction of the current frame signal of the chirp emission wave; an ambiguity multiple calculation module within a frame for judging the magnitude relationship between the center frequency shift value between the odd-numbered chirp emission wave and the even-numbered chirp emission wave and the predetermined threshold, and calculating the ambiguity multiple within a frame of the chirp emission wave by using the beat frequency and Doppler frequency of the chirp emission wave. Among them, when the center frequency shift value is less than the predetermined threshold, non-coherent accumulation within a frame, constant false alarm rate detection, and velocity ambiguity resolution processing within a frame are sequentially performed on at least two adjacent chirp emission waves to obtain the ambiguity multiple within a frame of the chirp emission wave; when the center frequency shift value is not less than the predetermined threshold, non-coherent accumulation of even-numbered chirp emission waves within a frame, constant false alarm rate detection, pairing of constant false alarm rate detection points within a frame, and velocity ambiguity resolution processing within a frame are sequentially performed on at least two adjacent chirp emission waves to obtain the ambiguity multiple within a frame of the chirp emission wave; a target information acquisition module for estimating the velocity of the target based on the ambiguity multiple within a frame to obtain the information of the target.

[0013] Optionally, the signal wave emission and reception module includes: the bandwidth, frequency modulation slope, and pulse width of each chirp signal of the chirp emission wave are the same.

[0014] Optionally, when the center frequency shift value is less than a predetermined threshold, the Doppler frequencies of the odd chirp transmitted wave and the even chirp transmitted wave are the same, the influence of the Doppler frequency on the beat frequency of the odd chirp transmitted wave and the even chirp transmitted wave is small, and the distances and Doppler positions corresponding to the odd chirp transmitted wave and the even chirp transmitted wave returned by the target are the same.

[0015] Optionally, the in-frame ambiguity multiple calculation module includes: calculating the ambiguous Doppler frequency of the chirp transmitted wave by using the beat frequency and the Doppler frequency of the chirp transmitted wave; calculating the in-frame ambiguity multiple of the chirp transmitted wave by using the ambiguous Doppler frequency, the pulse period of the chirp transmitted wave, and the center frequency shift value between the odd chirp transmitted wave and the even chirp transmitted wave.

[0016] Optionally, when the center frequency shift value is not less than a predetermined threshold, the in-frame ambiguity multiple calculation module includes: performing non-coherent accumulation of in-frame even chirp transmitted waves on at least two adjacent chirp transmitted waves in sequence by using two-dimensional fast Fourier transform.

[0017] Optionally, when the center frequency shift value is not less than a predetermined threshold, the Doppler frequencies of the chirp transmitted waves are different, the influence of the Doppler frequency of the chirp transmitted wave on the beat frequency is small, and the distances and Doppler positions corresponding to the odd chirp transmitted wave and the even chirp transmitted wave returned by the target are the same.

[0018] The third technical solution adopted by this application is: a computer-readable storage medium storing computer programs / instructions, and the computer programs / instructions are operated to execute the radar de-ambiguity method based on staggered transmission frequencies in Solution 1.

[0019] The fourth technical solution adopted by this application is: a computer device including a memory, a processor, and a computer program stored on the memory, and the processor executes the computer program to implement the radar de-ambiguity method based on staggered transmission frequencies in Solution 1.

[0020] The fifth technical solution adopted by this application is: a computer program product including computer programs / instructions, and when the computer programs / instructions are executed by a processor, the radar de-ambiguity method based on staggered transmission frequencies in Solution 1 is implemented.

[0021] The beneficial effects that the technical solutions of this application can achieve are: being able to meet the requirements of actual applications, the radar waveform having high-precision requirements and low system complexity requirements, having no special requirements for the sampling rate, storage capacity, and processing complexity of the radar system compared with traditional chirp waveforms, being able to accurately measure the distance and radial velocity simultaneously, and having high precision and resolution especially in the case of multiple targets in complex scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0023] Figure 1 It is a schematic diagram of a specific implementation manner of a radar ambiguity resolution method based on staggered emission frequencies in the present application;

[0024] Figure 2 It is a schematic diagram of the system flow of the present application;

[0025] Figure 3 It is a schematic diagram of the staggered linear frequency modulation waveform of the present application;

[0026] Figure 4 It is a schematic diagram of non-coherent accumulation within a frame of the present application;

[0027] Figure 5 It is a schematic diagram of coherent accumulation within a frame of the present application;

[0028] Figure 6 It is a schematic diagram of the magnitude relationship between odd Doppler frequencies and even Doppler frequencies of the present application;

[0029] Figure 7 It is a schematic diagram of a specific implementation manner of a radar ambiguity resolution device based on staggered emission frequencies in the present application.

[0030] Through the above-mentioned drawings, the clear embodiments of the present application have been shown, and there will be more detailed descriptions hereinafter. These drawings and textual descriptions are not intended to limit the scope of the concept of the present application in any way, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0031] The following will elaborate on the preferred embodiments of the present application in conjunction with the drawings, so that the advantages and features of the present application can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the protection scope of the present application.

[0032] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprising", "including" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising..." does not exclude the presence of additional identical elements in the process, method, article or device comprising the element.

[0033] High-resolution at long distances is of great significance for improving radar ranging accuracy, velocity measurement accuracy, multi-target resolution, and target detection and recognition. This is an important development direction for automotive radars. Theoretically, there are two methods to achieve high-resolution at long distances for radars. One is to emit extremely narrow pulses. By using this method, a large instantaneous bandwidth can be obtained to achieve high-resolution at long distances. However, emitting extremely narrow pulses will inevitably reduce the average power of the signal, thereby limiting the operating range of the system. Moreover, narrow pulses also require the system to have an extremely high sampling rate, which is very difficult to achieve with the current device level. At the same time, it also has relatively high requirements for data storage. The other is to use pulse compression methods to generate broadband signals. This is a commonly used method in current high-resolution radars. The chirp waveform in this method has the ability to extract the range and velocity parameters of multiple targets and has become a commonly used waveform for automotive radars.

[0034] This article proposes a radar ambiguity resolution method based on staggered transmit frequencies. This method presents a new waveform that meets the requirements of practical applications. Transmitting and receiving this radar waveform can accurately measure the range and radial velocity simultaneously. The new waveform consists of two chirp sequences with staggered transmit frequencies, achieving in-frame velocity ambiguity resolution, effectively avoiding the problem of incorrect target pairing between frames, and also having relatively high target estimation accuracy in the case of multiple targets.

[0035] Next, specific embodiments will be used to elaborate in detail on the technical solution of this application and how the technical solution of this application solves the above technical problems. The specific embodiments described below can be combined with each other to form new embodiments. For the same or similar ideas or processes described in one embodiment, they may not be repeated in some other embodiments. Next, the embodiments of this application will be described with reference to the accompanying drawings.

[0036] Figure 1 An embodiment of a radar ambiguity resolution method based on staggered transmit frequencies of this application is shown.

[0037] Figure 1 The radar ambiguity resolution method based on staggered transmit frequencies shown in the figure includes: Step S101, waveform design step, where the radar transmits at least two interleaved chirp transmit waves and receives the chirp transmit waves returned by the target. Among them, there is a center frequency shift between two adjacent chirp transmit waves, and the at least two interleaved chirp transmit waves include odd chirp transmit waves and even chirp transmit waves;

[0038] Step S102, parameter calculation step, calculating the beat frequency of the chirp transmit wave by performing fast Fourier transform in the range direction of the current frame signal of the chirp transmit wave, and calculating the Doppler frequency of the chirp transmit wave by performing fast Fourier transform in the Doppler direction of the current frame signal of the chirp transmit wave;

[0039] Step S103, in-frame ambiguity multiple acquisition step, judging the magnitude relationship between the center frequency shift value between the odd chirp transmit wave and the even chirp transmit wave and a predetermined threshold, and calculating the in-frame ambiguity multiple of the chirp transmit wave by using the beat frequency and Doppler frequency of the chirp transmit wave. Among them, when the center frequency shift value is less than the predetermined threshold, non-coherent accumulation in the frame, constant false alarm rate detection, and in-frame velocity ambiguity resolution processing are performed on at least two adjacent chirp transmit waves in sequence to obtain the in-frame ambiguity multiple of the chirp transmit wave; when the center frequency shift value is not less than the predetermined threshold, non-coherent accumulation of the even chirp transmit wave in the frame, constant false alarm rate detection, pairing of constant false alarm rate detection points in the frame, and in-frame velocity ambiguity resolution processing are performed on at least two adjacent chirp transmit waves in sequence to obtain the in-frame ambiguity multiple of the chirp transmit wave;

[0040] Step S104, target information acquisition step, estimating the velocity of the target according to the in-frame ambiguity multiple to obtain the information of the target.

[0041] This specific implementation method can meet the requirements of actual applications. The radar waveform has high-precision requirements and low system complexity requirements. Compared with the traditional chirp waveform, this application has no special requirements for the sampling rate, storage capacity, and processing complexity of the radar system, and can accurately measure the distance and radial velocity simultaneously. Especially in the case of multiple targets in a complex scene, it also has high precision and resolution.

[0042] Specifically, the working environment of automotive radars is complex. They need to effectively identify targets such as trees on both sides of the road, various signs, guardrails between lanes, vehicles on the road, and obstacles in the air and in the distance. Therefore, when designing the radar system, any false alarm situations should be avoided, and all targets in the observation area should be detected with a high probability. Information such as the distance, speed, and angle of the target should be obtained with high precision, high resolution, and high update rate. Therefore, detection performance is the primary consideration for automotive radars. To meet the requirements of automotive radar systems, the present invention proposes a radar waveform with low system complexity that meets the actual application requirements and high-precision requirements, as well as a corresponding radar ambiguity resolution method. This application designs a chirp (linear frequency modulation) system waveform with staggered transmit frequencies. Its large-bandwidth signal can obtain high-range-precision information, and the staggered transmit frequency waveform can effectively extract the target speed information within a frame. Even in the case of multiple targets, it has high precision and resolution, effectively avoiding the influence of the traditional inter-frame speed error space on the target precision.

[0043] Figure 2 is a schematic diagram of the system flow of this application. As Figure 2 shown, design a radar transmit wave as Figure 3 shown, and use the vehicle-mounted radar to transmit at least two interleaved linear frequency modulation transmit waves and use the vehicle-mounted radar to receive the linear frequency modulation transmit waves returned by the target. After receiving the linear frequency modulation transmit waves returned by the target, calculate the range-direction FFT (Fast Fourier Transform) in the fast time of the transmitted and returned linear frequency modulation transmit waves to obtain the beat frequency of the linear frequency modulation transmit wave, and calculate the slow-time Fast Fourier Transform of the odd current-frame signal and the slow-time Fast Fourier Transform of the even current-frame signal of the linear frequency modulation transmit wave respectively to obtain the odd Doppler frequency and the even Doppler frequency of the linear frequency modulation transmit wave. The above calculations are to obtain the target range and Doppler information of the odd and even frames. When the center frequency difference is less than the threshold, the range and Doppler positions corresponding to the odd and even pulses of the target are the same. Therefore, the phase method is used to estimate the ambiguity multiple; when the center frequency difference is greater than the threshold, the ranges corresponding to the odd and even pulses of the target are the same, but the Doppler positions are different. At this time, the ambiguity multiple is resolved by pairing targets with the same range but different speeds. Then, when the frequency shift of the center frequency of the linear frequency modulation transmit wave, that is, Figure 2 the frequency difference in, is small, perform non-coherent integration within the frame, constant false alarm rate detection, and velocity ambiguity resolution processing within the frame; when the frequency shift of the center frequency of the linear frequency modulation transmit wave is large, perform coherent integration of the odd linear frequency modulation transmit wave within the frame and coherent integration of the even linear frequency modulation transmit wave within the frame for the odd and even linear frequency modulation transmit waves within the frame respectively, as well as perform constant false alarm rate detection and pairing processing of constant false alarm rate detection points within the frame and velocity ambiguity resolution processing within the frame; use the ambiguity multiple within the frame obtained by the above processing to estimate the velocity of the target, and finally obtain the information of the target.

[0044] In Figure 1 the illustrated embodiment, the radar ambiguity resolution method based on staggered transmit frequencies includes a step S101 of waveform design, where the radar transmits at least two interleaved chirp transmit waves and receives the chirp transmit waves returned by the target. Among them, there is a center frequency shift between two adjacent chirp transmit waves, and the at least two interleaved chirp transmit waves include odd chirp transmit waves and even chirp transmit waves.

[0045] In a specific embodiment of the present application, transmitting at least two interleaved chirp transmit waves by the radar includes: the bandwidth, chirp slope, and pulse width of each chirp signal of the chirp transmit waves are the same.

[0046] Specifically, a vehicle-mounted radar is used to transmit a staggered chirp transmit sequence signal with two different center frequencies outward and receive the returned signal. The total duration of the signal frame transmitted by the radar is 2LT chirp where L is the number of odd-frame transmit pulses, and T chirp is the pulse period of the signal transmitted by the radar. The transmitted waveform of the radar consists of two interleaved chirp sequences. Each chirp signal has the same bandwidth, chirp slope, and pulse width, except that there is a center frequency shift f shift between two adjacent chirps. A specific example diagram thereof is as shown in Figure 2 .

[0047] The mathematical expressions corresponding to the odd chirp transmit wave and the even chirp echo are as follows. Here, the beat frequency, Doppler frequency, and the target are related. When the target position and speed are different, the beat frequency and Doppler frequency will change accordingly:

[0048] s1(t,k) = exp(j2π(f B1 t - f D1 ·2k·T chirp + Φ1))

[0049] s2(t,k) = exp(j2π(f B2 t - f D2 ·2k·T chirp + Φ2))

[0050] where s1(t) is the odd pulse in the pulse sequence, s2(t) is the even pulse in the pulse sequence, f B1 , f B2 are the beat frequencies of the odd pulse and the even pulse respectively, which describe the difference between the transmission and reception instantaneous frequencies of the signal wave. It is related to the target range shift and radial velocity. f D1 and f D2They are the odd Doppler frequency and the even Doppler frequency respectively, and T chirp is the pulse period of the transmitted signal, k is the corresponding number of transmitted pulses, Φ1 and Φ2 are the initial transmission phases, and the beat frequency f B is obtained by performing FFT on each chirp signal, and the Doppler frequency f D is obtained by performing FFT along the slow time dimension in the same range cell.

[0051] During the calculation process, according to s1(t), s2(t), T chirp and k, and the f B1 calculated by subsequent algorithms, B2 f D1 f D2 the ambiguity multiple is estimated.

[0052] In Figure 1 the shown embodiment, the radar ambiguity resolution method based on staggered transmit frequencies includes a step S102 parameter calculation step, calculating the beat frequency of the current frame signal of the chirp transmit wave by performing a fast Fourier transform in the range direction within the frame, and calculating the Doppler frequency of the current frame signal of the chirp transmit wave by performing a fast Fourier transform in the Doppler direction.

[0053] In Figure 1 the shown embodiment, the radar ambiguity resolution method based on staggered transmit frequencies includes a step S103 in-frame ambiguity multiple acquisition step, determining the magnitude relationship between the center frequency shift value between the odd chirp transmit wave and the even chirp transmit wave and a predetermined threshold, and calculating the in-frame ambiguity multiple of the chirp transmit wave by using the beat frequency and Doppler frequency of the chirp transmit wave, where the center frequency shift value is a parameter value that can be obtained when the radar transmits. And when the center frequency shift value is less than the predetermined threshold, performing in-frame non-coherent integration, constant false alarm rate detection, and in-frame velocity ambiguity resolution processing on at least two adjacent chirp transmit waves in sequence to obtain the in-frame ambiguity multiple of the chirp transmit wave; when the center frequency shift value is not less than the predetermined threshold, performing in-frame non-coherent integration of the even chirp transmit wave, constant false alarm rate detection, pairing of in-frame constant false alarm rate detection points, and in-frame velocity ambiguity resolution processing on at least two adjacent chirp transmit waves in sequence to obtain the in-frame ambiguity multiple of the chirp transmit wave.

[0054] In a specific embodiment of the present application, when the center frequency shift value is less than the predetermined threshold, the Doppler frequencies of the odd chirp transmit wave and the even chirp transmit wave are the same, the influence of the Doppler frequency on the beat frequencies of the odd chirp transmit wave and the even chirp transmit wave is small, and the distances and Doppler positions corresponding to the odd chirp transmit wave and the even chirp transmit wave returned by the target are the same.

[0055] Further, when the center frequency shift value is less than a predetermined threshold, non-coherent accumulation within a frame, constant false alarm rate detection, and velocity ambiguity resolution within a frame are sequentially performed on at least two adjacent chirp emission waves to obtain the ambiguity multiple within a frame of the chirp emission wave, including: calculating the ambiguous Doppler frequency of the chirp emission wave using the beat frequency and Doppler frequency of the chirp emission wave; calculating the ambiguity multiple within a frame of the chirp emission wave using the ambiguous Doppler frequency, the pulse period of the chirp emission wave, and the center frequency shift value between the odd chirp emission wave and the even chirp emission wave.

[0056] Specifically, the magnitude of the center frequency shift value is the difference between the emission center frequencies of the odd and even frames. Among them, the center frequency of the emission signal is designed in advance, so its magnitude is determined by whether the Doppler positions are consistent. If the Doppler positions are consistent, it indicates that the center frequency shift value is relatively small, and the phase method is used to calculate the ambiguity multiple. If the Doppler positions are inconsistent, the frequency method is used to calculate the ambiguity multiple. Among them, the threshold for judging the magnitude of the center frequency shift value is related to the Doppler resolution, that is, it is related to other parameters of the radar during system design. The present application does not limit its specific value.

[0057] Figure 4 is a schematic diagram of non-coherent accumulation within a frame of the present application. As Figure 4 shown, when the center frequency shift value is not less than the predetermined threshold, the phase difference corresponding to the odd and even pulses at this time is:

[0058]

[0059] where f D,amb is the ambiguous Doppler frequency, which is obtained by acquiring the target information detected by CFAR (constant false alarm rate), q is the velocity ambiguity number, c is the speed of light, Δφ is the phase difference corresponding to the odd and even pulses, is the range ambiguity number.

[0060] Extract the phase information of the odd two-dimensional FFT and the even two-dimensional FFT corresponding to the CFAR (constant false alarm rate) detection target, and then calculate the velocity ambiguity number q within the frame according to the phase difference between the detected targets of the odd and even chirp emission waves that have been calculated, using the above formula and the parameter information obtained or calculated. The present application can ensure that the true velocity of the target can be obtained when calculating the target information by changing the solution of the velocity ambiguity number q to the solution of the range ambiguity number.

[0061] In a specific embodiment of the present application, when the center frequency shift value is not less than a predetermined threshold, non-coherent accumulation of even chirp transmitted waves within a frame, constant false alarm rate detection, pairing of constant false alarm rate detection points within a frame, and velocity ambiguity resolution processing within a frame are sequentially performed on at least two adjacent chirp transmitted waves, and obtaining the ambiguity multiple within a frame of the chirp transmitted wave includes: when the center frequency shift value is not less than a predetermined threshold, using two-dimensional fast Fourier transform to perform non-coherent accumulation of even chirp transmitted waves within a frame on at least two adjacent chirp transmitted waves in sequence.

[0062] Furthermore, when the center frequency shift value is not less than a predetermined threshold, there are differences in the Doppler frequencies of the chirp transmitted waves, the influence of the Doppler frequencies of the chirp transmitted waves on the beat frequency is small, and the distances and Doppler positions corresponding to the odd and even chirp transmitted waves of the target return are the same.

[0063] Specifically, Figure 5 is a schematic diagram of coherent accumulation within a frame of the present application, as Figure 5 shown, the odd and even chirp transmitted waves respectively satisfy the following limiting conditions:

[0064]

[0065] wherein, f D1 and f D2 are the odd Doppler frequency and the even Doppler frequency respectively.

[0066] Here, q1 and q2 are different velocity ambiguity numbers. After performing constant false alarm rate target detection on the odd and even chirp transmitted waves, target pairing within a frame is performed according to the distance between the target and the radar and the different velocities of the target. At this time, the true velocity of the target is:

[0067]

[0068] According to whether f D1 and f D2 are numbers less than zero and the relative magnitude relationship between f D1 and f D2 the relationship between these two ambiguous Doppler frequencies and their calculation relationship with Δf D2,amb and f D1,amb can be calculated, that is, the Doppler ambiguity multiple can finally be obtained through the above calculation. D

[0069] According to the calculated Δf D relationship formula, the velocity v of the target can be calculated, and then through the formula a high-precision Doppler estimate value can be obtained.

[0070] ​Among them, according to f D1 and f D2 whether it is a number less than zero and the relative magnitude relationship between f D1 and f D2 , the relationship between f D2,amb and f D1,amb of these two fuzzy Doppler frequencies and its calculation relationship with Δf D can be calculated, Figure 6 is a schematic diagram of the magnitude relationship between the odd Doppler frequency and the even Doppler frequency of this application. As Figure 6 shown, the corresponding relationship of its specific calculation process is as follows:

[0071] a. f D1,amb ≥0, f D1,amb ≤f D2,amb ; q2 = q1, Δf D = f D2,amb - f D1,amb

[0072] b. f D1,amb ≥0, f D2,amb <0, f D1,amb - f D2,amb > f D,max ; q2 = q1 + 1, Δf D = f D2,amb + 2f D,max - f D1,amb

[0073] c. f D1,amb ≤0, f D2,amb <0, f D1,amb < f D2,amb ; q2 = q1, Δf D = f D2,amb - f D1,amb

[0074] d. f D1,amb ≤0, f D2,amb ≥0, f D2,amb - f D1,amb < f D,max ; q2 = q1, Δf D = f D2,amb - f D1,amb

[0075] e. f D1,amb ≤0, f D2,amb ≤0, f D2,amb < f D1,amb ; q2 = q1, Δf D = f D2,amb - f D1,amb

[0076] f.f D1,amb ≤0, f D2,amb ≥0, f D2,amb -f D1,amb >f D,max ; q2 = q1 - 1, Δf D = f D2,amb -2f D,max -f D1,amb

[0077] g.f D1,amb ≥0, f D2,amb ≥0, f D1,amb >f D2,amb ; q2 = q1, Δf D = f D2,amb -f D1,amb

[0078] h.f D1,amb ≥0, f D2,amb ≤0, f D1,amb >f D2,amb ; q2 = q1, Δf D = f D2,amb -f D1,amb 。

[0079] In Figure 1 the illustrated embodiment, the radar ambiguity resolution method based on staggered transmit frequencies includes a step S104 of target information acquisition, where the speed of the target is estimated according to the in-frame ambiguity multiple to obtain the target information.

[0080] Figure 7 Illustrates a specific embodiment of a radar ambiguity resolution device based on staggered transmit frequencies according to the present application.

[0081] In Figure 7 the illustrated specific embodiment, the radar ambiguity resolution device based on staggered transmit frequencies mainly includes: a signal wave transmitting and receiving module 701, configured to use the radar to transmit at least two interleaved linear frequency modulation transmit waves and receive the linear frequency modulation transmit waves returned by the target, where there is a center frequency shift between two adjacent linear frequency modulation transmit waves, and the at least two interleaved linear frequency modulation transmit waves include odd linear frequency modulation transmit waves and even linear frequency modulation transmit waves;

[0082] a parameter calculation module 702, configured to calculate the beat frequency of the linear frequency modulation transmit wave by performing an in-frame range direction fast Fourier transform on the current frame signal of the linear frequency modulation transmit wave, and calculate the Doppler frequency of the linear frequency modulation transmit wave by performing a Doppler direction fast Fourier transform on the current frame signal of the linear frequency modulation transmit wave;

[0083] The in-frame ambiguity multiple calculation module 703 determines the magnitude relationship between the center frequency shift value between the odd chirp transmitted wave and the even chirp transmitted wave and a predetermined threshold, and calculates the in-frame ambiguity multiple of the chirp transmitted wave by using the beat frequency and Doppler frequency of the chirp transmitted wave. Among them, when the center frequency shift value is less than the predetermined threshold, incoherently accumulate, constant false alarm rate detection, and in-frame velocity ambiguity resolution processing are performed on at least two adjacent chirp transmitted waves in sequence to obtain the in-frame ambiguity multiple of the chirp transmitted wave; when the center frequency shift value is not less than the predetermined threshold, incoherently accumulate the in-frame even chirp transmitted wave, constant false alarm rate detection, in-frame constant false alarm rate detection point pairing, and in-frame velocity ambiguity resolution processing are performed on at least two adjacent chirp transmitted waves in sequence to obtain the in-frame ambiguity multiple of the chirp transmitted wave;

[0084] The target information acquisition module 704 is used to estimate the velocity of the target according to the in-frame ambiguity multiple to obtain the information of the target.

[0085] In a specific embodiment of the present application, the signal wave transmitting and receiving module includes: the bandwidth, frequency modulation slope, and pulse width of each chirp signal of the chirp transmitted wave are the same.

[0086] In a specific embodiment of the present application, when the center frequency shift value is less than the predetermined threshold, the Doppler frequencies of the odd chirp transmitted wave and the even chirp transmitted wave are the same, the influence of the Doppler frequency on the beat frequency of the odd chirp transmitted wave and the even chirp transmitted wave is small, and the distances and Doppler positions corresponding to the odd chirp transmitted wave and the even chirp transmitted wave returned by the target are the same.

[0087] In a specific embodiment of the present application, the in-frame ambiguity multiple calculation module includes: calculating the ambiguous Doppler frequency of the chirp transmitted wave by using the beat frequency and Doppler frequency of the chirp transmitted wave; calculating the in-frame ambiguity multiple of the chirp transmitted wave by using the ambiguous Doppler frequency, the pulse period of the chirp transmitted wave, and the center frequency shift value between the odd chirp transmitted wave and the even chirp transmitted wave.

[0088] In a specific embodiment of the present application, the in-frame ambiguity multiple calculation module includes: when the center frequency shift value is not less than the predetermined threshold, using two-dimensional fast Fourier transform to perform incoherently accumulation of the in-frame even chirp transmitted wave on at least two adjacent chirp transmitted waves in sequence.

[0089] In a specific embodiment of the present application, when the center frequency shift value is not less than a predetermined threshold, there are differences in the Doppler frequencies of the chirp emission waves. The influence of the Doppler frequencies of the chirp emission waves on the beat frequency is small, and the distances and Doppler positions corresponding to the odd chirp emission waves and the even chirp emission waves returned by the target are consistent.

[0090] The radar ambiguity resolution device based on staggered emission frequencies provided by the present application can be used to execute the radar ambiguity resolution method based on staggered emission frequencies described in any of the above embodiments. Its implementation principle and technical effects are similar and will not be elaborated here.

[0091] In a specific embodiment of the present application, each functional module in a radar ambiguity resolution device based on staggered emission frequencies of the present application can be directly in hardware, in a software module executed by a processor, or in a combination of both.

[0092] The software module can reside in a RAM memory, a flash memory, a ROM memory, an EPROM memory, an EEPROM memory, a register, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. The exemplary storage medium is coupled to the processor such that the processor can read information from and write information to the storage medium.

[0093] The processor can be a central processing unit (CPU for short), or can also be other general-purpose processors, digital signal processors (DSP for short), application specific integrated circuits (ASIC for short), field programmable gate arrays (FPGA for short), or other programmable logic devices, discrete gate or transistor logic, discrete hardware components, or any combination thereof. The general-purpose processor can be a microprocessor, but in an alternative, the processor can be any conventional processor, controller, microcontroller, or state machine. The processor can also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors combined with a DSP core, or any other such configuration. In an alternative, the storage medium can be integrated with the processor. The processor and the storage medium can reside in an ASIC. The ASIC can reside in a user terminal. In an alternative, the processor and the storage medium can reside in the user terminal as discrete components.

[0094] In another specific embodiment of the present application, a computer-readable storage medium stores computer programs / instructions, and the computer programs / instructions are operated to execute the radar ambiguity resolution method based on staggered transmit frequencies described in the above embodiments.

[0095] In a specific embodiment of the present application, a computer device includes a memory, a processor, and a computer program stored on the memory. The processor executes the computer program to implement the radar ambiguity resolution method based on staggered transmit frequencies described in the above embodiments.

[0096] In a specific embodiment of the present application, a computer program product includes computer programs / instructions, and when the computer programs / instructions are executed by a processor, the radar ambiguity resolution method based on staggered transmit frequencies described in the above embodiments is implemented.

[0097] In several embodiments provided by the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed couplings or direct couplings or communication connections to each other can be through some interfaces. The indirect couplings or communication connections of the devices or units can be in electrical, mechanical or other forms.

[0098] The units described as separate components may or may not be physically separated. The components displayed as units may or may not be physical units, that is, they can be located in one place, or they can be distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0099] The above are only the embodiments of the present application, and do not limit the patent scope of the present application. All equivalent structural transformations made using the content of the specification and drawings of the present application, or directly or indirectly applied in other related technical fields, are equally included in the patent protection scope of the present application.

Claims

1. A radar deambiguation method based on staggered transmission frequency, characterized in that: include: Using a radar to transmit at least two intertwined linear frequency modulation transmission waves and receiving the linear frequency modulation transmission waves returned by a target, wherein there is a center frequency shift between two adjacent linear frequency modulation transmission waves, and the at least two intertwined linear frequency modulation transmission waves include an odd-numbered linear frequency modulation transmission wave and an even-numbered linear frequency modulation transmission wave; Calculate the intra-frame distance of the current frame signal of the linear frequency modulation transmission wave to obtain the beat frequency of the linear frequency modulation transmission wave by fast Fourier transform, and calculate the Doppler fast Fourier transform of the current frame signal of the linear frequency modulation transmission wave to obtain the Doppler frequency of the linear frequency modulation transmission wave; The step of obtaining the intra-frame blur multiple is to determine the magnitude relationship between the center frequency shift value between the odd-numbered linear frequency modulation transmission wave and the even-numbered linear frequency modulation transmission wave and a predetermined threshold, and to calculate the intra-frame blur multiple of the linear frequency modulation transmission wave using the beat frequency and the Doppler frequency of the linear frequency modulation transmission wave, wherein: When the center frequency shift value is less than a predetermined threshold, performing intra-frame non-coherent accumulation, constant false alarm rate detection and intra-frame speed defuzzification processing on at least two adjacent linear frequency modulation transmission waves in sequence to obtain an intra-frame fuzzification multiple of the linear frequency modulation transmission wave; When the center frequency shift value is not less than a predetermined threshold, at least two adjacent linear frequency modulation transmission waves are sequentially subjected to intra-frame even linear frequency modulation transmission wave non-coherent accumulation, constant false alarm rate detection, intra-frame constant false alarm rate detection point pairing and intra-frame speed defuzzification processing to obtain an intra-frame fuzzification multiple of the linear frequency modulation transmission wave; The target information acquisition step estimates the speed of the target according to the blur multiple within the frame to obtain the target information.

2. The radar deambiguation method based on staggered transmission frequency according to claim 1, characterized in that: The method of transmitting at least two intertwined linear frequency modulation transmission waves by radar includes: The bandwidth, frequency modulation slope and pulse width of each linear frequency modulation signal of the linear frequency modulation transmission wave are the same.

3. The radar deambiguation method based on staggered transmission frequency according to claim 1, characterized in that: When the center frequency shift value is less than a predetermined threshold, the Doppler frequencies of the odd-numbered linear frequency modulation transmission wave and the even-numbered linear frequency modulation transmission wave are consistent, the Doppler frequency is less affected by the beat frequency of the odd-numbered linear frequency modulation transmission wave and the even-numbered linear frequency modulation transmission wave, and the distances and Doppler positions corresponding to the odd-numbered linear frequency modulation transmission wave and the even-numbered linear frequency modulation transmission wave returned by the target are consistent.

4. The radar deambiguation method based on staggered transmission frequency according to claim 1, characterized in that: When the frequency shift value of the center frequency is less than a predetermined threshold, at least two adjacent linear frequency modulation transmission waves are sequentially subjected to intra-frame non-coherent accumulation, constant false alarm rate detection, and intra-frame speed defuzzification processing to obtain an intra-frame fuzzification multiple of the linear frequency modulation transmission wave, including: Calculating the fuzzy Doppler frequency of the linear frequency modulation transmission wave using the beat frequency and the Doppler frequency of the linear frequency modulation transmission wave; The intra-frame fuzzy multiple of the linear frequency modulation transmission wave is calculated by using the fuzzy Doppler frequency, the pulse period of the linear frequency modulation transmission wave and the center frequency shift value between the odd-numbered linear frequency modulation transmission wave and the even-numbered linear frequency modulation transmission wave.

5. The radar deambiguation method based on staggered transmission frequency according to claim 1, characterized in that: When the center frequency shift value is not less than a predetermined threshold, at least two adjacent linear frequency modulation transmission waves are sequentially subjected to intra-frame even linear frequency modulation transmission wave non-coherent accumulation, constant false alarm rate detection, intra-frame constant false alarm rate detection point pairing, and intra-frame speed defuzzification processing to obtain an intra-frame fuzzification multiple of the linear frequency modulation transmission wave, which includes: When the center frequency shift value is not less than a predetermined threshold, two-dimensional fast Fourier transform is used to sequentially perform intra-frame even-number linear frequency modulation transmission wave non-coherent accumulation on at least two adjacent linear frequency modulation transmission waves.

6. The radar deambiguation method based on staggered transmission frequency according to claim 1, characterized in that: When the center frequency shift value is not less than a predetermined threshold, there is a difference in the Doppler frequencies of the linear frequency modulation transmission waves, the Doppler frequencies of the linear frequency modulation transmission waves have little influence on the beat frequency, and the distances and Doppler positions corresponding to the odd-numbered linear frequency modulation transmission waves and the even-numbered linear frequency modulation transmission waves returned by the target are consistent.

7. A radar deambiguation device based on staggered transmission frequency, characterized in that: include: A signal wave transmitting and receiving module, used for transmitting at least two interlaced linear frequency modulation transmission waves by using a radar and receiving the linear frequency modulation transmission waves returned by a target, wherein there is a center frequency shift between two adjacent linear frequency modulation transmission waves, and the at least two interlaced linear frequency modulation transmission waves include an odd-numbered linear frequency modulation transmission wave and an even-numbered linear frequency modulation transmission wave; A parameter calculation module, used for calculating the intra-frame distance fast Fourier transform of the current frame signal of the linear frequency modulation transmission wave to obtain the beat frequency of the linear frequency modulation transmission wave, and calculating the Doppler fast Fourier transform of the current frame signal of the linear frequency modulation transmission wave to obtain the Doppler frequency of the linear frequency modulation transmission wave; The intra-frame fuzzy multiple calculation module determines the magnitude relationship between the center frequency shift value between the odd-numbered linear frequency modulation transmission wave and the even-numbered linear frequency modulation transmission wave and a predetermined threshold value, and calculates the intra-frame fuzzy multiple of the linear frequency modulation transmission wave by using the beat frequency and the Doppler frequency of the linear frequency modulation transmission wave, wherein, when the center frequency shift value is less than the predetermined threshold value, at least two adjacent linear frequency modulation transmission waves are sequentially subjected to intra-frame non-coherent accumulation, constant false alarm rate detection, intra-frame constant false alarm rate detection point pairing, and intra-frame speed defuzzification processing to obtain the intra-frame fuzzy multiple of the linear frequency modulation transmission wave; when the center frequency shift value is not less than the predetermined threshold value, at least two adjacent linear frequency modulation transmission waves are sequentially subjected to intra-frame even-numbered linear frequency modulation transmission wave non-coherent accumulation, constant false alarm rate detection, intra-frame constant false alarm rate detection point pairing, and intra-frame speed defuzzification processing to obtain the intra-frame fuzzy multiple of the linear frequency modulation transmission wave; The target information acquisition module is used to estimate the speed of the target according to the intra-frame blur multiple to obtain the target information.

8. A computer-readable storage medium storing a computer program / instruction, characterized in that: The computer program / instructions are operated to perform the radar deambiguation method based on staggered transmission frequency as described in any one of claims 1-6.

9. A computer device comprising a memory, a processor and a computer program stored in the memory, characterized in that: The processor executes the computer program to implement the radar deambiguation method based on staggered transmission frequencies according to any one of claims 1 to 6.

10. A computer program product comprising a computer program / instructions, characterized in that When the computer program / instruction is executed by a processor, the radar deambiguation method based on staggered transmission frequency as described in any one of claims 1 to 6 is implemented.

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